Process for improving the heads of railway rails



Patented June 17, 1 930 UNITED STATES JACOB LUKA SCZYK, OF ROSENBERG, OBERPFALZ, -GERMAI \TY PROCESS FOR TMPROVING THE HEADS F RAILWAY RAILS No Drawing. Application filed August 25, 1927, Serial No. 215,514, and in- Germany October 21, 1920.

Attempts to increase the efficiency and economy of railway operation has led to continually higher speeds and continually greater wheel pressures of the locomotives and vehicles. The development of thetracks has however not kept pace with this, and the result thereof is greater wear of the rails, so that more particularly on tracks having sharp curves and steep grades they have only 0 a relatively short length of life. The heavy Wear of the rails can be met by thickening the rail profile, or more particularly by employing a steel rail having a higher resistance to wear.

5 Attempts hitherto made to provide a harder steel rail having a tensile strength of 80 and more kilogrammes per square mil1i metre have not been satisfactory, because it has been ascertained that resistance to wear to and tensile strength are essentially dilferent things. The employment of hard steel, howover, such as corresponds to .thisstrength, bringsdangers into railway operation, because the hard steel rail no longer has sufli- 5 cient tenacity, and the prescribed deflection i? the 1bending test is very barely obtained, i at a l.

' Now it has been foundthat the resistanceof the rails to wear canybe enhanced toan extent corresponding to present-day requirements if the steel rail, in the outer zone of the rail head, which is subjected to the greatest wear when being run over, is converted into a texture resembling martensite. -This 5 texture shows an unusually .greatpowerof resistance to the stresses' arising in operatipn during the practical utilization of the rail, so that rails in which the outer zone of the head is converted into-martensite, according' to the results of the tests for wear that have been systematically carriedout, must have a much longer life than the known rails. It is important, and on the lines of the present invention: is attainable, when onl the L5 outer zone of the rail head is converte into must beof such duration that the rail head owing'to the heat remaining in the rail foot martensite, While the rail foot and web are not converted at all, and thereby maintain their high tenacity, which is of the utmost importance, in practical operation.

'lhe conversion'of the external zone of the rail head into martensite is eflected by energetically quenching the warm pieces of rail cut to length, by plunging the rail head into cold water, employing a suitable appliance which prevents warping. This immersion assumes a black appearance, and that after being taken out of the bath it does not be; come red again. After the removal from the bath an improvement of the rail head occurs and the rail web, which have not been cooled.

It has been found that the temperature of the rail head after the quenching should not rise above 450C, in order that a good result may be ensure The appropriate duration for the immersion depends upon the composition of the, steel. When working for example with steels having a carbon content of from 0.40 to O.45 per cent. the time of'immersion varies between 1% and minutes, the lower immersion time corresponding to the higher carbon content.

Experimentshave shown that the resistance to wear on my treads of rails improved in the rail head by the new process is far more than ten times as eat as'that of ordinary rails made from t e same unimproved material. i

What I claim is':--

The process of increasing the resistance of railway rails to wear, said rails having a carbon content'between 0.40 and 0.45 per cent,

usual in commercial rails, which process 5 comprises, first cutting the rail to the desired length and-then plunging the head of the rail while still retalning its rolling heat into cold water for a length of time varying from 1%, minutes for the low carbon content .to minute for the high carbon content so that the rail-head assumes a. black appear ance and that the temperature of the railhead after removal from the water does not exceed 450 C. and does not again become red while the foot and Webof the rail remain Warm, whereby only the outer zone of the rail-head is given a martensite structure.

In testimony whereof I have signed my name to this specification.

' JACOB LUKASCZYK. 

